Amazon.com Inc.'s Japan unit said it will partially suspend a deal with a major book distributor next month in an apparent bid to challenge longtime industry distribution practices by asking more publishers to make their works available to the online retailer.

Amazon Japan K.K. notified major publishing companies in writing last Friday that it will stop asking Nippon Shuppan Hanbai Inc. at the end of June to secure relatively older books if they are out of stock at the time of order.

"Please consider a switch to direct deals" as it will help deliver books to customers more quickly, Amazon said in the notification to publishers.

Nippon Shuppan Hanbai, more widely known as Nippan, declined to comment on Amazon Japan's plan.

Nonetheless, Amazon Japan said it will continue working with the Tokyo-based distributor for new books and other publications in stock.

"The supply from Nippan focuses on best-sellers and is typically for offline retailers (bookstores)," Amazon Japan said in a statement Monday.

Its practices do not match Amazon's business model of selling a variety of books in smaller lots, both newer and older, even though they may not generate strong sales, Amazon Japan said.

Still, Amazon said it will ask Tohan Corp., another major book distribution agency, to continue delivering manga and magazines.

Book publishers have traditionally controlled the distribution industry as well, but Amazon Japan's move "symbolizes a trend" in which retailers have an increasingly bigger influence, said Akira Nagae, a writer well-versed with the industry.

It seems Amazon intends to procure more direct deals with publishers because it believes they can ensure quicker delivery times compared with traditional major distributors who do not keep many books in stock, Nagae said.